1. Field of the Invention
The present invention relates to vacuum pumps, and more particularly relates to vacuum pumps for removing air from relatively small containers.
2. Description of the Prior Art
Electrically driven vacuum pumps are known in the prior art. However, these vacuum pumps tend to be relatively expensive and are not capable of operation without a source of electric power. In addition to electric vacuum pumps, manually operable (i.e. manually driven) vacuum pumps are known, specifically for laboratory use. Manually operable vacuum pumps commonly utilize a single step process to achieve a suitable endvacuum. Typically, the manually operable vacuum pumps produce an endvacuum of approximately 0.3 Psi absolute.
German patent number DE 4,138,114 discloses a sorption cooling system including sorption medium which, under vacuum conditions, adsorbs steam from a water reservoir. As a result of the adsorption of steam, the liquid which remains in the water reservoir cools and may even solidify to form ice. Typically, in order for the water to cool to 0.degree. C. and solidify, a vacuum pressure of approximately 0.08 Psi should be present within the sorption cooling system. Ideally, a manually operable vacuum pump should easily and quickly provide a suitable vacuum pressure throughout the entire sorption cooling system. However, presently known manually driven vacuum systems are incapable of easily and efficiently removing air from a connected sorption cooling system or other device.